Role of N-glycosylation in the expression and functional properties of human AT1 receptor

Biochemistry. 1999 Jul 6;38(27):8621-7. doi: 10.1021/bi9830516.


The role of N-glycosylation in the pharmacological properties and cell surface expression of AT1 receptor was evaluated. Using site-directed mutagenesis, we substituted both separately and simultaneously the asparagine residues in all three putative N-linked glycosylation consensus sequences (N-X-S/T) of AT1 receptor (positions 4, 176, and 188) with aspartic acid. Expression of these mutant receptors in COS-7 cells followed by photolabeling with [125I]-[p-benzoyl-Phe8]AngII and SDS-PAGE revealed ligand-receptor complexes of four different molecular sizes, indicating that the three N-glycosylation sites are actually occupied by oligosaccharides. Binding studies showed that the affinity of each mutant receptor for [Sar1,Ile8]Ang II was not significantly different from that of wild-type AT1 receptor. Moreover, the functional properties of all mutant receptors were unaffected as evaluated by inositol phosphate production. However, the expression levels of the aglycosylated mutant were 5-fold lower than that of the wild-type AT1 receptor. Use of green fluorescent protein-AT1 receptor fusion proteins in studying the cellular location of the aglycosylated mutant demonstrated that it was distributed at a much higher density to the ER-Golgi complex than to the plasma membrane in HEK 293 cells. Together, these results suggest an important role of N-glycosylation in the proper trafficking of AT1 receptor to the plasma membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites / genetics
  • COS Cells
  • Glycosylation
  • Green Fluorescent Proteins
  • Humans
  • Luminescent Proteins / genetics
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Receptor, Angiotensin, Type 1
  • Receptor, Angiotensin, Type 2
  • Receptors, Angiotensin / biosynthesis*
  • Receptors, Angiotensin / genetics
  • Receptors, Angiotensin / metabolism*
  • Receptors, Angiotensin / physiology
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism
  • Recombinant Fusion Proteins / physiology
  • Transfection


  • Luminescent Proteins
  • Receptor, Angiotensin, Type 1
  • Receptor, Angiotensin, Type 2
  • Receptors, Angiotensin
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins